Adjustable mounting for ring gears



W. C. JOHNSON ADJUSTABLE MOUNTING For; RING GEARS April 23, 19436.

2 Sheets-Sheet 1 Filed July 15, 1944 F m b W M. a

April 3, 1946. w. c. JOHNSON 2,399,122

ADJUSTABLE MOUNTING FOR RING GEARS Filed July 15, 1944 v 2 Sheets-Sheet 2 o M M/wyy Patented Apr. 23, 1946 UNITED STATES PATENT- OFFICE ADJUSTABLE MOUNTING FOR RING GEARS William C. Johnson, Wauwatosa, Wis., assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis, a corporation of Delaware Application July: 15, 1944, Serial No; 545,141

7 Claims.

It has been customary prior to this invention to mount ring gears by bolting them onfi'anges directly attached to the driven mill or kiln drum;

This results in a structure which so long as the with reference, to: the accompanying, drawings in which:

Fig. 1 isa: fragmentary view of a rotary kiln or mill shell shown pa'rtiallyin longitudinal secthan through a; driving gear according to the invention;

Fig; 2 is an enlarged. fragmentary section. of the upper portion of the driving gear of Fig. 1, taken on the line- Ill-11 of Fig. 3;

Fig. a fragmentary end. view of a portion of the driving gear'of. Fig. 1, shown partly in section on the line III-III of Fig. 2

Fig- 4 is a detail end view of a driving ring according to the embodiment of the invention shown in'Fig. 1; I

Fig. 5 is a fragmentary cross-section through a drum. shell'showing; a modified form of ring. gear drum shell remains coaxial with the bearing jour;

nals will provide 'a coaxial gear held in concert tricity by friction. However, if there is a change in the bearing journal the ring gear will no longer remain coaxial but will be eccentric to the axis of rotation. Means must therefore. be provided to adjust the gear to coaxiality with the bearing journals. Furthermore the drum is subject. to

high temperature operating conditions which cause it. to expand. The ring gear, not being a part. of the drum andv equally heated at all times, is subjected to severe strains due to the thermal expansion or contraction of the drum relative thereto, and has often failed in service under-these strains.

It is an object of the present invention to pro vide a gear mounting in which a rigid ring gear may be readily adjusted to concentricity with th bearing journal. It is a further object of this invention to provide a mounting for a rigid ring gear on a rela tively expanding and contracting element which will provide for substantially free thermal "expansion of the mounting member relative to the ring gear while preserving a coaxial driving 'relation of the gear relative to the bearingjournal, thus relieving the. ring' gear from strains dueto thermal expansion of the mounting-member. Y

More'particularly' this. invention relates to" a structure for mounting gears. in which a device is provided for attaching a rigid ring gearin co.- axial driving relation with a driven element, the device providing for substantially free radial ex pension. and contraction of thedriven element relative. to the ring gear.

The invention having the above and 'other'ob- ,jects which may appear herein may be carried into practical effect as hereinafter fully described mounting according tothe invention; and

Fig. 6 is a section. on the line VIVI of Fig. 5. Si'milarreference characters refer to similar parts throughout the several views'oi the drawmgs.

In Fig. 1 ofthe drawings byway of example, a: preferred embodiment of the driving gear of this invention. is shown in connection with a kiln or'mill having adrum or shell I equipped, for example, with riding: rings or'tires 2 forming a bearingjournal supported on supporting bearings 3. In place of tires 2 and bearings 3 as shown, the drnmobviously may be supported onany other suitable known type of bearing (not shown) providing, for rotation of the drum on a fixed 1ongitudinal axis.

' The drum l may. or may not be provided with a reinforcing pad: 4, and a driving flange 5 may be mounted on such pad 4 or directly on the drum l in driving relation thereto. In order to provide for adjustment of the driving gear to concentrici'tywith the drum or bearing axis, an intermediate driving ring T provided with enlarged bolt holes 8 maybe secured to the flange 6 by bolts 9 in an obvious manner. For adjustment,

a. plurality ofradiallyextending adjusting screws Il may be threadedly engaged. in'radial holes: in the inner periphery of ring I. Theendsof screws Il may bear on; thesuriace of. flange 61 as: shown in Figs. 1, 2 and 3'.

In the outeredge of ring '1 there may be cut a series of similar radially extending slots l2 equiangularly spaced about the circumference of the ring, each slot l2 having parallel sides as clearly shown inFigs'I) and 4. The number of slots may be 'any' integral number greater than 2, that is, there must-be. at least three slots;

A toothed ring gear l3 of rigid circular-form may have an annular web It extending radially inwardly and provided with extensions, for example, bolts I0, having a square shank or intermediate block I1, may be secured to web I4 in a circle concentric with the pitch circle, being held rigidly in place by nuts I8. The lateral extensions formed by bolt shank II are arranged in number and location to correspond with slots I2 in ring I, and have a tangential dimension equal to the width of slots I 2, and flt slidably in slots I2. Slots I2 being truly radial to ring'i and shanks or projections I! being arranged concentric to the pitch circle of ring gear I3, driving ring I and ring gear I3 will be coaxially related regardless of thermal expansion of ring gear I3 relative to annular driving ring I. or vice versa. The ring gear I3 may be held in axially fixed coaxial driving relation with driving ring I as by plain washer I 9 and Belleville spring washer 2| against which a nut 22 on bolt I 8 may be tight ened to a desired degree. The pressure exerted between flange I 4 and ring I will depend on the spring tension on Belleville Washer 2! and which will be chosen to create a limited frictional holding force which will limit the amount of radial strain which may be transferred between ring I and flange I4 due to relative thermal expansion or contraction, to a degree which will be safe, permitting radial motion between flange I4 and ring I to occur under a fairly low strain. There will, due to this arrangement, be substantial freedom of relative expansion and contraction of ring gear I3 and ring 1, within practical limits, without danger of rupture of ring gear I3 due to thermal expansion of ring I and drum I which may become heated to a much higher temperature in service than ring gear I3. This relative expansion and contraction may occur without disturbing the coaxial relationship of ring gear I3 to the bearing journals represented by riding rings or tires 2.

A gap 23 is left between flange I 4 and flange B to provide for relative centering adjustment.

Destruction in service of the coaxial relation between bearing journals 2 and ring gear I3 may be compensated for by adjustment of ring I with relation to drum I'by loosening bolts 9 and alining ring I with journals 2 by adjustment of screws I I.

Obviously slots I2 might be formed in flange I4 and bolts I 6 secured in ring I, such an arrangement being a full mechanical equivalent (not shown) to the structure of Figs. 1-4.

A second embodiment of this invention is illustrated in Figs. 5 and 6 of the drawings in which drum I is similar to that shown in Fig. 1. Driving flange 6 is shown secured directly to drum I. Intermediate or driving ring I! is. adjustably mounted by bolts 9 in enlarged holes 8 and-adjustably centered by adjusting screws II in a manner similar to ring I in Figs. 1-3.

Ring I 01 may be formed as an annulus, L;- shaped in cross-section with the axially extending flange I'III adjustable to concentricity with bearing journals 2.

Ring gear H3, similar outwardly to ring gear I3, may have a web 4 and an inner axially extending flange I I of larger inner diameter than flange Ilt of ring I01. Ring gear H3 may be secured according to the invention in coaxial driving relation with flange IIO by. obliquely or tangentially extending bars I20 of identicalmaterial characteristic shape and size joined as by weld.- ing at opposite endsto flanges H5 and IIO, respectively, as at angularly spaced points I24 and I25. The bars I20 will be formed so that the sections between flanges H5 and I I0 will normally be substantially straight and have an axial width reater than their thickness. Material will be chosen so that expansion, for example, of ring I01 relative to ring gear I I3 will cause equal bending of bars I20 without transmitting any force of dangerously high degree to ring gear I I3. The ring gear I13 will therefore remain in coaxial driving relation to ring I01 and substantial free dom of relative expansion and contraction of ring gear H3 and ring I0'I will be provided. The

radial forces transmittable will be limited by the low resistance to bending in the plane of the gear of the bars I20 to a degree well within the strength of gear H3. A slight relative angular motion of gear I I3 and ring I01 will occur upon relative expansion or contraction thereof without destroying their coaxial driving relationship.

Obviously bars I20 may be secured to ring gear II 3 and ring I07 by any other suitable known means (not shown) which willpermit the relationship hereinabove disclosed to be maintained.

While specific embodiments of the invention have been illustrated and described, it will be understood that the invention is intended to include such modifications and equivalents as may readily occur to persons skilled in the art and is limited only by the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In a gear structure, the combination comprising a driven element subject to severe changes in operating temperature, a rigid ring gear, a rigid annular power transmitting member mounted on said driven element in driving relation, means for adjusting the position of said annular member relative to said driven element to set it in a position concentric with the axis of rotation of said element and yieldable means connecting said ring gear and said annular member in coaxial driving relation, said yieldable means being constructed and arranged to provide for substantially free thermal expansion andcontraction of said driven element and said annular member relative to said ring gear.

2: In a drum'drive, a gear mounting flange mounted in driving relation on said drum, an auxiliary ring adjustably mounted in driving relation with said flange, centering means for adjusting said ring relative to said flange to center said ring with relation to the true axis of rotation of said drum, a rigid circular ring gear, and yieldable means connecting said ring gear to said auxiliary ring in coaxial driving relation, said yieldable means being constructed and arranged to yield at safe stresses and maintain concentricity of said ring gear and auxiliary ring during relative thermal expansion and contraction thereof.

3. In a drum drive, a gear mounting flange, an annular driving ring adjustably mounted in driving relation to said flange, centering means for adjusting said ring relative to said flange to center said ring with relation to the true rotational axis of said drum, a ring gear and means connecting said ring gear and said driving ring in coaxial driving relation, said means being radially deformable to permit relative thermal expanding and contracting motion of said ring gear and said driving ring without disturbin their concentricity and without causing any appreciablemechanical stress in said ring gear.

4. In an adjustable mounting for ring gears, a

rotatable element, a driving ring member mounted on said element in driving relation, centering means for adjusting said ring relative to said rotatable element to center said ring with relation to the axis of rotation of said rotatable element, a circular ring gear member, yieldable means connecting said ring gear member and said driving ring member in coaxial driving relation, comprising at least three radial slots in at least one of said coaxial members substantially equiangu- Early spaced about its periphery, and a corre sponding number of projections on the other of said members arranged in a circle concentric therewith and each having a maximum tangential dimension equal to the width of the slots in the first said member, said projections being engaged in said slots to maintain said members in coaxial driving relation, and provide for substantially free, relative thermal expansion of said members.

5. A gear having a rigid annular member mounted for rotation on its axis, a rigid ring gear membenand means securing said annular memher and said ring gear member in coaxial driving relation, said means comprising at least three substantially equiangularly spaced radial slots in one of said members and a corresponding number of projections on the other of said members arranged in a circle concentric therewith, each said lug having a maximum tangential dimension equal to the width of its corresponding slot and being engaged therein to maintain said members in coaxial driving relation and provide for substantial freedom of relative thermal expansion of said members.

6. A gear comprising a rigid annular member mounted for rotation on its axis, a rigid ring gear member, and means for securing said annu- V lar member and said ring gear member in coaxial driving relation, said means comprising at least three substantially equiangularly spaced arms of identical material characteristics, shape and size, each secured at one end to said annular member and at the other end to said ring gear member at a point angularly removed from said first end, said arms being suificiently flexible in the plane of said gear to provide for substantially free relative thermal expansion of said annular member and said ring gear member.

7. In an adjustable mounting for ring gears, a rotatable element, a driving ring member mounted on said element in driving relation, centering means for adjusting said ring relative to said element to center said ring with relation to the axis of rotation of said element, a rigid ring gear member, yieldable means connecting said ring gear member and said driving ring member in coaxial driving relation comprising at least three substantially straight equiangularly spaced arms of substantially identical material characteristics, shape and size, each arm secured at one end to said annular member and at the other end to said ring gear member at a point angularly removed from said first end, said arms being sufliciently flexible in the plane of said gear to pro--' vide for substantially free relative thermal ex- 

